BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	nation,
	o_year,
	sum(amount) as sum_profit
from
	(
		select
			n_name as nation,
			extract(year from o_orderdate) as o_year,
			l_extendedprice * (1 - l_discount) - ps_supplycost * l_quantity as amount
		from
			part,
			supplier,
			lineitem,
			partsupp,
			orders,
			nation
		where
			s_suppkey = l_suppkey
			and ps_suppkey = l_suppkey
			and ps_partkey = l_partkey
			and p_partkey = l_partkey
			and o_orderkey = l_orderkey
			and s_nationkey = n_nationkey
			and p_name like '%seashell%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3528908.79..3528913.83 rows=144 width=46) (actual time=283981.144..287249.490 rows=175 loops=1)
   Buffers: shared hit=30088292 read=888211 dirtied=199 written=7454
   ->  Sort  (cost=3528908.79..3528909.15 rows=144 width=46) (actual time=283968.083..284871.620 rows=3265515 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 557518kB
         Buffers: shared hit=30088292 read=888211 dirtied=199 written=7454
         ->  Nested Loop  (cost=2858578.62..3528903.63 rows=144 width=46) (actual time=127560.788..263200.667 rows=3265515 loops=1)
               Buffers: shared hit=30088284 read=888211 dirtied=199 written=7454
               ->  Nested Loop  (cost=2858578.62..3528862.56 rows=144 width=24) (actual time=127560.688..242334.804 rows=3265515 loops=1)
                     Buffers: shared hit=23557254 read=888211 dirtied=199 written=7454
                     ->  Nested Loop  (cost=2858578.62..3528577.28 rows=144 width=24) (actual time=127560.632..165907.598 rows=3265515 loops=1)
                           Buffers: shared hit=10778816 read=586734 written=1460
                           ->  Merge Join  (cost=2858578.62..3528535.34 rows=144 width=28) (actual time=127560.564..141201.306 rows=3265515 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=965122 read=586734 written=1460
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.049..6533.419 rows=7999945 loops=1)
                                       Buffers: shared hit=309155 read=125053 written=1459
                                 ->  Sort  (cost=2858578.05..2867532.94 rows=3581956 width=28) (actual time=127560.423..130170.384 rows=3265515 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353423kB
                                       Buffers: shared hit=655967 read=461681 written=1
                                       ->  Hash Join  (cost=66998.61..2468640.66 rows=3581956 width=28) (actual time=2089.664..123430.068 rows=3265515 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=655964 read=461681 written=1
                                             ->  Seq Scan on lineitem  (cost=0.00..1683568.23 rows=60644823 width=24) (actual time=0.039..26956.892 rows=59984826 loops=1)
                                                   Buffers: shared hit=649736 read=427384 written=1
                                             ->  Hash  (cost=65522.00..65522.00 rows=118129 width=4) (actual time=2089.425..2089.425 rows=108947 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3831kB
                                                   Buffers: shared hit=6225 read=34297
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=118129 width=4) (actual time=0.026..2006.626 rows=108947 loops=1)
                                                         Filter: ((p_name)::text ~~ '%seashell%'::text)
                                                         Rows Removed by Filter: 1891053
                                                         Buffers: shared hit=6225 read=34297
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.006..0.006 rows=1 loops=3265515)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9813694
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.97 rows=1 width=8) (actual time=0.022..0.022 rows=1 loops=3265515)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=12778438 read=301477 dirtied=199 written=5994
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.004..0.004 rows=1 loops=3265515)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6531030
 Total runtime: 287358.037 ms
(43 rows)

COMMIT;
COMMIT